That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

Springtails are minute, primitive, wingless insects classified in the Order Collembola.  Over 6,000 species are found in most temperate and tropical habitats, where they figure importantly in the diets of Poison Frogs (Dendrobates, Phyllobates, Oophaga), small salamanders and newly metamorphosed amphibians of many kinds. Please see Part I of this article for information on procuring Springtails and their role in helping to save the nearly extinct Kihansi Spray Toad (Nectophrynoides asperginis). Read More »

I’m frequently contacted by amphibian keepers who find that their pets are floating about at the water’s surface and seem unable to submerge.  While gas produced by bacteria within the animal can cause this, the most frequent culprit is Gas Bubble Disease.  This term is sometimes used to refer to any of several related but different maladies, and commonly afflicts African Clawed Frogs (Xenopus laevis), Dwarf Clawed Frogs (Hymenochirus spp.) and Mexican Axolotls (Ambystoma mexicanum). Read More »

The diets of captive Poison Frogs (Dendrobates, Phyllobates, Oophaga), Mantellas, small salamanders (i.e. Red-Backed Salamanders) and tiny, newly-transformed amphibians are usually limited to the two readily available foods of appropriate size – pinhead crickets and fruit flies.  The minute, wingless insects known as Springtails (Order Collembola) are easy to procure and rear, and offer a convenient means of increasing dietary variety for small amphibians.

Natural Diets of Smaller Amphibians

Most small terrestrial frogs and salamanders forage among leaf litter, which is invariably inhabited by thousands of species of tiny invertebrates (surprisingly, the weight of invertebrates in most habitats exceeds that of all vertebrates combined!).  It seems certain that these amphibians consume an extremely varied diet in the wild, and that typical captive diets do not meet their nutritional needs.

Aphids (1/8-inch-long green or red insects found in colonies on plant stems) are an option, but these are becoming scarce in many areas and, with their complicated life history (involving sex-switching and other unique twists), are difficult to maintain long-term.  One can also collect ants, tiny beetles and other leaf litter invertebrates (please see article below), but of these only Springtails can be easily bred in large numbers.

Problematical Captives

Some amphibians are so small that even pinhead crickets prove too large a meal.  I’ve run into this situation with Kihansi Spray Toads (Nectophrynoides asperginis), which are a mere ¾ inch long when full grown.  These toads, now likely extinct in the wild, give birth to fully formed toadlets that are so small as to be barely visible.  A steady supply of Springtails was essential to the successful rearing of these Tanzanian natives, the last of their kind on earth.  Folks breeding other tiny amphibians, such as Strawberry Poison Frogs (Oophaga pumilio), will also find Springtail colonies an invaluable resource.

Procuring Springtails

With over 6,000 species identified thus far, Springtails are common in most temperate and tropical habitats.  They usually appear as tiny white “dots” jumping about below fallen leaves.  You can start a colony by scooping them up in the leaf litter or by purchasing any of the several species available through commercial suppliers.  Most breed well in captivity and can build up enormous populations under favorable conditions – please see Part II of this article for details.

Further Reading

Whenever possible, the diets of smaller amphibians should be supplemented with wild-caught invertebrates.  Please see Collecting Leaf Litter Invertebrates for some useful techniques.

Strawberry Poison Frog image referenced from wikipedia and originally posted by Encarna Sáez Goñalons & Víctor Martínez Moll

Springtail image referenced from wikipedia and originally posted by Mvuijlst

Central and South American frogs of the family Dendrobatidae secrete virulent skin toxins (histrionicotoxins, batrachotoxins and others) when disturbed.  Many people believe that the toxins of many species of Poison Frogs, known also as “Poison Arrow Frogs” and “Dart Poison Frogs”, were once used to coat darts and arrows used in hunting and warfare.  Actually, this is not the case – but the actual facts are no less interesting.

Origin of Frog Toxins

Poison Frog toxins are derived from the diet, being concentrated and synthesized from chemicals within the ants and millipedes (and possibly other invertebrates) upon which the frogs feed.  Wild-caught frogs gradually lose their protective toxins after a time in captivity… captive-born Poison Frogs do not develop toxic skin secretions unless they are fed the appropriate types of invertebrates.

Some years ago, I was fortunate enough to be at the National Aquarium in Boston when the origin of Poison Frog toxins was being investigated.  In one experiment, Green and Black Poison Frogs (Dendrobates auratus) that had lost their skin toxicity were liberated in the aquarium’s huge rainforest exhibit.  When recaptured some time later, the frogs had regained their potent skin toxins.  Studies showed that the source of these toxins were invertebrates that had been transported to the exhibit in soil and on tropical plants.

Toxin Use in Hunting

The use of frog toxins on hunting darts was first reported in the literature in 1823, by British naval captain C. Cochrane.  He reported that certain forest-dwelling people collected Golden Poison Frogs (Phyllobates terribilis) and confined and fed the frogs until toxins were needed.  The frogs were pierced with a stick in order to induce the secretion of the toxins, which appeared as white froth on the skin.

Up to 50 darts could be treated with the secretions from a single frog, and the darts were reported to retain their potency for at least 1 year.  A jaguar shot with a poison-coated dart was said to die within 4-5 minutes, and monkeys and smaller animals were killed instantly.

Darts, and not arrows, were utilized for hunting…toxin use on arrows shot from bows has never been observed.

Toxins were used in this manner by the Mucushi, Chaco and, possibly, other groups of people.

Toxins and Warfare

It comes as a surprise to many folks that frog toxins have never been documented as being used in wars or against human enemies.

Frog Species Utilized

The skin secretions of only 3 species of frog have been identified as being used as dart coatings.  These frogs are not, as often believed, the familiar Dendrobates species, but rather belong to the related genus Phyllobates.  Frogs belonging to this genus are less commonly seen in the pet trade than Dendrobates, although one, the Golden Poison Frog (P. terribilis), is fairly well-established in captivity.

Medicines from Frog Skin

The skin toxins of a great many frogs, related and unrelated to the Dendrobatids, are highly complex and are being studied with a view towards developing medications that may be useful in oncology and infectious disease research.  A compound derived from the secretions of the Phantasmal Poison Frog (Epipedobates tricolor) shows great promise as a pain medication…it is more effective than morphine, non-addictive and non-sedating.

Further Reading

You can read more about studies on the medicinal value of frog toxins here.

Golden Poison Frog image referenced from wikipedia and originally posted by Wilfried Berns

Live plants are very useful in creating amphibian terrariums that are both attractive to the eye and beneficial for the animals housed therein.  However, amphibian skin is permeable to substances as small as oxygen molecules.  Several readers have recently questioned whether pesticides used on terrarium plants could harm amphibians through physical contact.

Examples of Contact Poisoning

Most chemicals do readily penetrate the skin of frogs and salamanders and can kill them in short order.  Pesticides on plants are a concern, even though they will not be consumed.

A coworker of mine once lost a group of Blomberg’s Toads and Smoky Jungle Frogs after confining them to quickly-rinsed enclosure that had been cleaned with Nolvasan, and I witnessed a Leopard Frog expire after being put into a pail that had previously housed a Fowler’s Toad (the stressed toad had apparently released skin toxins).

Locating Safe Plants

Some commercial growers who cater to zoos and the pet trade claim not to use pesticides.  The reptile department of your local zoo, if reachable, might be a good place to start when searching for reputable plant suppliers.  Pet stores specializing in tropical fishes usually buy pesticide-free plants as well. Some, especially those that carry plants for outdoor ponds, may stock emergent species or others suitable for use with amphibians.

Removing Surface Pesticides

If you are unsure of pesticide presence, discard the soil that arrived with the plant and rinse the plant, roots and all, vigorously.  Finish up by submerging the plant and swishing it about underwater.  Some recommend a light soap solution, but I have not found this to be necessary.

Systemic Pesticides

A greater potential concern is posed by systemic pesticides, which do not remain on the surface but rather work their way into the plant’s tissues.  Fortunately, these are not commonly used with on commercially raised plants suitable for terrariums.

One colleague of mine did run into a situation involving systemic pesticides.  He held the plants for 30 days before introducing them to his exhibits.  He had no problems with any of several tree frog species that utilized the plants frequently, and eventually used them with arboreal salamanders (Bolitoglossa spp.) as well.  This time frame is based on observation rather than rigid testing, but has proven quite dependable.

Further Reading

Those who keep herbivorous turtles and lizards also need to be concerned about potentially lethal plants.  The species listed in my article Common Plants that are Toxic to Birds  should be avoided by herp keepers as well.

To learn about growing safe plants for herbivorous reptiles, please see Reptile Gardens.